Fish given cannabis by scientists in bid to relax them

With the aquaculture industry ramping up production, increased numbers of fish in the same confined spaces is resulting in underwater trouble.

One group of scientists reckoned cannabis may provide a solution.

Hakai Magazine reports scientists at the American University of Beirut fed Nile Tilapia fish pellets laced with cannabis oil to test whether they would relax and possibly grow faster.

The hope was that THC - the active ingredient in cannabis - would lower the incidences of "intraspecific interactions", or fish bullying in farms.

Before the study began its lead author, Patrick Saoud, was facing issues trying to find cannabis in Lebanon, where people caught in possession are generally sent to prison.

He called the country's attorney general to ask advice, who was apparently surprised at having never been asked such a question before.

It turned out there was nothing in Lebanese law preventing what Dr Saoud was proposing and local police were able to provide the team with cannabis from their evidence locker.

Unfortunately, the fish that ate the THC-laden pellets did not survive any better than those on the control diet.

The fish may have built up a tolerance after being fed the same amount of THC continuously for two straight weeks, leading to diminished effectiveness.

However, the cannabis did increase the fish's metabolisms, making them hungrier; to feed them more would cut into the farmer's profit margins and in turn make any gains from cannabis feeding negligible.